Maryland officials have told Metro to stop shutting down escalators and using them as stairways in subway stations, saying that the practice violates state law and puts passengers and the machines at risk.

The warning has alarmed Metro managers, who say it could force them to shut down the entrances to 14 of Metro's 21 stations in Maryland.

At station entrances where there are only two escalators and one has been taken out of service for repairs, Metro has routinely frozen the other escalator so that passengers can walk in and out of the station. Such shutdowns soon will become far more widespread as Metro this month launches a five-year project to rebuild 170 escalators throughout the transit system.

But escalators are not designed to withstand the constantly shifting weights of passengers walking up and down, said Rudy Gondeck, Maryland's chief elevator and escalator inspector. That pressure can shorten the lifespan of an escalator, he said.

Walking on an escalator also creates a tripping hazard for passengers, Maryland officials said, because the steps are as much as three-fourths of an inch higher than those on most stairways and have metal ridges that run together, making them difficult to see.

Metro officials deny that their policy is unsafe and say that if the transit system is barred from using escalators as stairways, it will be impossible to complete the escalator overhaul project without closing station entrances.

"This means any time we took one of the escalators out of service to work on it, we'd have to barricade the other one," Metro spokesman Ray Feldmann said. "We'd have to close entrances to the stations any time we took one of the escalators out of service."

Metro managers and Maryland officials are meeting today to air their differences on the issue and try to negotiate a solution.

Maryland officials are insisting that Metro put up barriers to prevent passengers from using any frozen escalator, which would leave the elevator as the only means in and out of some stations. State inspectors said that they have the power to impose fines on Metro if it refuses to comply but that they hope to avoid taking such action.

"We don't want to shut down the stations," Gondeck said. "But this has been a problem for some time and we've got to take a step back and try to resolve a few things."

Gondeck said his office has been aware of the problem for at least 10 years but is getting tough about enforcement now because Metro's escalator rebuilding program will take more escalators out of service than ever before.

"An escalator is a power-driven, inclined, continuous stairway used for raising or lowering passengers," Gondeck said. "What does that mean to you? Continuous means moving."

Metro says its escalators can withstand the pounding feet of passengers and the arrangement poses no risk to people.

"This is a textbook case of bureaucratic regulations being applied without common sense and with a total disregard for our passengers," Feldmann said. "Our top priority is passenger safety and in no way has passenger safety been compromised by this longtime practice."

Paul C. Gillum Jr., director of Metro's plant maintenance department, acknowledged that the practice will compound wear and tear on the escalators. "Does this present some additional maintenance concerns? Absolutely," Gillum said. "But we also have to be concerned about passengers being able to exit and enter the stations."

In addition to freezing exterior escalators, Metro for years has often shut down escalators that lead from station mezzanines to platforms and used them as stairways to improve crowd flow at busy times and reduce electricity costs. Those shutdowns, too, are a violation of Maryland law, according to state officials.

Virginia has no state escalator code; regulation of escalators varies from county to county. Arlington County, which has the most Metro stations in Virginia, does not claim jurisdiction over Metro.

Staff writer Emily Wax contributed to this report.

CAPTION: A construction worker uses the Columbia Heights station escalator in September.